The field of the invention is apparatus and methods for cleaning workpiece or wafer containers.
In the semiconductor device manufacturing industry, and related industries, flat media, such as semiconductor wafers, memory media, optical devices and masks, and similar flat media, are stored or transported in containers. The containers help to protect the wafers or similar objects from contamination and/or physical damage, during the manufacturing processes. Various types of containers are used, including open containers, such as cassettes, carriers or trays, as well as closable or sealable containers or boxes, including FOUP, FOSB, SMIF pods or boxes.
These containers are often used to contain and transport metal plated wafers, and especially wafers plated with copper. The metal or copper plated wafers may be loaded and unloaded into and out of a container over one hundred times, before processing of the wafers into semiconductor devices is complete. As a result of contact between the plated wafer and the container surfaces, and via abrasion and vibration, the wafer holding or contacting surfaces within the containers often become contaminated with metal residue or particles. This contamination of the containers is especially problematic with copper contamination, which can be highly disruptive to the wafer manufacturing process.
Accordingly, there is a need for methods and apparatus for removing metallic contamination, and especially copper contamination, from wafer containers.